Numerical investigation of the pebble bed structures for HCCB TBM

Abstract The packing structures of tritium breeder and neutron multiplier pebble beds are important to estimate the thermal mechanical properties and the flow characteristics of purge gas in solid tritium breeding blanket. In this study, the pebble packing structures were numerical studied based on DEM simulation. The packing structures of cylinder pebble beds were further analyzed. The results show that the aspect ratio has a great influence on packing structure of pebble bed. Increasing the aspect ratio, a higher average packing factor can be obtained. Further, the U-shaped Li 4 SiO 4 pebble beds were investigated. The results show that when the width of the U-shaped channel, the height of the bed and the diameter of the pebbles are given, the dimensions of the U-shaped container have little effect on the pebble bed packing structures. In addition, the influences of pebble size on packing structures of U-shaped pebble bed were analyzed and discussed. By decreasing the pebble size, the average packing factor can be increased, the wall effect region of the U-shaped pebble bed can be also reduced relatively and a more uniform pebble bed can be obtained.